A tripod camera with focussing adjustments is far more likely to give satisfactory results than the box-form fixed-focus variety. The better the quality of the lens and the larger the aperture it works at satisfactorily, the more chance the flashlight will have of giving a fully-exposed picture.
THE QUESTION OF SMOKE is always to be considered, and no flash lamp or flashlight mixture has yet been made which, if used unconfined, does not create a certain amount. Some, however, are worse than others. This is a nuisance and a serious drawback if a second or third attempt is desired soon after the first, as it is impossible to get a clear picture through the haze. Windows and doors should, therefore, be promptly opened after the flash and a draught encouraged, to clear the air quickly.
A method of trapping the smoke is to be recommended if much work is done, and some such device as the following can be employed. A large tin biscuit box is obtained and the lid removed. The box is used on its side with the open end pointed towards the sitter. A small metal tray is suspended from the roof of the inside of the box, and upon the tray is placed a charge of gun cotton and magnesium or flash powder. A sheet of glass should be made to slide in front of the box, or if the middle of the lid is cut away, leaving only the rim, this can be used to hold the glass. A small flap door should be made at the back - opening outwards to allow the expulsion of air after the flash has occurred. The powder is fired by means of a lighted taper inserted through a small hole in the side of the box. Immediately after the flash the flap door should be tightly closed, the box removed to the open air and the smoke allowed to escape.
THE DEVELOPMENT of flashlight negatives calls for much the same attention that hand-camera snapshots require. A developer readily giving an image free from hardness is to be recommended, and a well-diluted pyro-metol formula, as follows, has given good results in my hands :
Metasulphite of potash..............
Bromide of potash...........
Carbonate of soda.............
Use equal parts of both.
The following metol developer can be relied upon to produce a good soft negative and minimise any tendency towards harshness caused by faulty lighting :
Sulphite of soda...........
Carbonate of potash.........
Add potassium bromide if necessary.
Rodinal, Azol, Certinal, Rembrol and Victol are all soft working single-solution developers that only need dilution with water to secure excellent negatives of flashlight subjects.